Epidemiological research on HFMD death cases Based on the assumption that the early use of antipyretic drugs and host factors are the risk factors of death, this research will focus a comparative analysis for mild, critical and death cases of hand, foot and mouth disease on early use of antipyretic drug type, host factors, pathogen factors. We try to identify/ the illness progress of death cases and related impact factors. Through the investigation, we try to describe the epidemiological features, clinical features, diagnosis, treatment and exposure history, and enhance the understanding about the severe case to provide evidence for reducing the fatality rate. 2. Population-based Virus Carriage Rate Survey In order to understand whether it is related between seasonal prevalence or outbreaks of the hand, foot and mouth disease with virus carriage rate in population, we will carry out population-based, one-year round enterovirus (EV71 and CoxA16, other enterovirus) carriage rate survey in one HFMD higher-prevalence and one lower-prevalence district or county of one province. Target groups include healthy people, normal people who have closely contacted with the severe cases or ordinary HFMD cases. The aim is to analyze the proportion and dynamic changes of silently infected among these different groups and its role in the spread of HFMD so as to support the formation of HFMD prevention and control strategies.